1. Field of the Invention
This invention relates to apparatus for charging rechargeable batteries, and more particularly, to apparatus for recharging rechargeable batteries which provides multiple regulated constant charging currents and accordingly variable charging power by using different charging current settings.
2. Description of the Prior Art
U.S. Pat. No. 3,829,676 describes a rechargeable flashlight apparatus for use in a vehicle. The apparatus uses constant voltage rather than constant current. There is no provision for providing a fixed or predetermined constant charging current for the apparatus. The charging current varies as a consequence of variations of power source voltage and the number of cells being charged, and no visual indications of the charging status of the apparatus is provided.
U.S. Pat. No. 3,890,555 describes another battery charging system using constant voltage. The apparatus will allow for the charging of only a fixed number of cells. Switching transistors, in combination with a diode, are required for visual indication of the system status.
U.S. Pat. No. 4,092,580 discloses a rechargeable battery apparatus for a flashlight. The apparatus may be incorporated into an automotive electrical system. A pair of lamps are used to indicate whether the charging circuitry is in a high or in a low mode or status. The high or the low mode is selectively engaged by the user. The lamps also act as current limiters for charging purposes and as fuses for the protection of the circuitry.
Copending application Ser. No. 964,944, by the same inventor as the present application, describes battery charging apparatus for charging rechargeable batteries using regulated constant current. Visual indications by light emitting diodes (LEDs) are also provided. The apparatus is satisfactory for many recharging purposes, but the apparatus has an inherent limitation as to the amount of charging current available for charging, due to current capacity of the integrated circuit regulator.
The apparatus of the present invention utilizes regulated constant current sources and multiple current settings to provide for the simultaneous charging of a number of rechargeable batteries or cells at various charging currents and at current values exceeding the maximum current capacity of a single integrated circuit regulator.